Process for preparing organosilanes



Patented Oct. 9, 1951 UNKT PAT E NT 0 F F ICE? PROCESSFQRPRERARING, ORGAN OSILAN ES RobertDeWaldLipscomb, Wilmington, DeL', as-

sig'nor toE; I'L- dufPont de Nemours- & Company, Wilmington; Dela, incorporation. of. Delaware:

No Drawing Application Januar 30; 1948, Serial-No. 5,502

19 Glaiins.- (Cl. 2.60.448 .2)

This'inv'entio'n relates to organic compounds of silicon and more particu'l-arly'to" aimethod for their preparation.

Organohalosilanes haveabeen prepared in the past by various methodssuch .as by the reaction of, a.Grignard reagenton.tetrahalosilanes and' by the reaction. of hallosilanes with, polymeriza'ble olefinic hydrocarbons, in the. presence of peroxy catalysts. The former method involves the use of.therelativelyexpensive G rignard reagent.v The latter method has certain disadvantages. among whichlsmhe fact that the method using peroxy atalysts gives veryjjsmail yields, of the desired organohalosilanes when thereacti'on is carried.

out. in" metal. equ pment and th.us is disadvan1- tage1ous' in; commercial operations. p

This invention'has as anobjectthe preparation oforganohalosilanes, A further object is the provision :of a new process for thepreparation of organohalosilane's. hereinafter.

These objects arexaccomplished by the following invention wherein a ha'losilane having at least one hydrogen on 1. thesilicon atom-isheated with an't'orgarriccompound having at least one non-aromatic or 'ol'eiinic double bond,- i em, a doublebond'; aliphatic in character, betweentwocarbons; and hydrogen on at- Ie'astone dithedoubly bondedcarbons 1 under the i-niti'atow in fluence of organis azo compound wherein the azo -N N group isacyciic and -bonded from both of' thenitrogens to 'dineren-t carbons;

Among these; azo compounds-which are 'efi'ctive a-s catalysts, or more properly as initiators; those which are particularly eifecti ve, becaus'eoi their greater activity. in the reaction oi -"halojs-ilan'es with olefinic compounds are those'ha-ving' both valences of the 9.20 nitrogens' (-N='N-)- attached to difierent carbons which are non-aro matic, .i's. e.,.a1'ipI-iatic.-'oi1 cycloaliphatic; and at least one of which is tertiary which tertiary carbon has further attached. toit through another carbon a negative radical in which radical the three-remaining valences of thelatter 'carbon are satisfiedi by; at :least; one element or atom-ic.-'num ber 110F38 (oxygen. and/oienitrogen-i 1.. er, the? nitrile, carbonamidea and. carb'alkoxy groups: Carballi'oxy:groupsinw-hich the alkylf'group'; tainsifrom? one .torsix carbomatonist'are. preierredzz Titenegative radical inrgeneralf neutral: with respectt'oaciiiity and of thesezneutral radicals thc nitrile ie -preterred since theazonitrile are readiiy obtainednnd have highactivitys The azci nitrogen: in thcseiiiitiators are :acycli'c e., notpart of a ringi Y a other; object will appear temperatures Still more preferred arethe symmetricaiazobonsattached to three other carbons, attachedto the azonitrogens; and having; as negative group attached to the tertiary carbons; the nitrile, carbonamide or carbalkoxy group; in view of the fact that they are active as catalysts atlower than the unsymmetrical compounds.

Unsaturated compounds which-are especially suitable for carrying out theprocess of this invention are hydrocarbonshaving olefinic double bondsaliphatic in character, and having hyd rogen on at least one of the doubly bondedcar bons. Especially preferred are-those acyclic, aliphatic hydrocarbons containing but one unsaturation and that olefinic. and having hydrogen on both of-the'doubiy bonded carbons; The-products obtainable by the process of this-invention vary from condensation products of one" mole of the unsaturated compound withone mole of the halosiiane to products built up from several moles, e. g., two, three, four, or-moreoftheunsaturated organic compound with onemole of the halosilane, depending upon the particular reactants employed.

The-process of this; invention .isyreadily carried out by heating the olefinic compoundand the halosilane in the presence of a. small amount of theazo catalyst, and preferably under conditions which exclude moisture and which provide agitation of the reactants. For example, a hydrocarbon having an olefinic bond, such-as-ethyiene, loctene,v or l-octadecene, anda halosilane, such as trichlorosilane, are heated under anhydrous con-- ditions with from (3.1% to 5% .by weight of the azo'catalyst. The reaction temperature employed but they are ordinarily not necessary; At the completion .of the reaction. any unreactedcvolatile ingredients are separated from the reaction product, for example,- by distillation. Theresulting addition product can be used directly in those:

applications where a small amountof the azo catalyst or catalyst residue conihined iiiit is not harmful. If a product of higher quality is desired, the crude addition product can be purified by fractional distillation at ordinary or reduced pressure, or by other conventional methods.

The reaction can be carried out in glass or metal reaction vessels equipped with suitable means for agitating the reaction mixture, at substantially atmospheric or at elevated pressures, the particular pressure selected being dependent on the particular olefinic compoundbeing used and on the particular type of product desired. Various materials of construction can be employed for the reactors; stainless steel or silveror glass-lined steelreactors are very suitable, especially for reactions under high pressures. When the olefinic compound is a liquid at ordinary or only moderately elevated temabove atmospheric pressure.

4 of a liquid boiling at 99-136 C. which contains some of the reaction product of two moles of ethylene with one mole of trichlorosilane.

Example III tinued for hours under these conditions during peratures, the process of this invention is conveniently carried out at refiux temperature under a slight additional pressure of an inert gas such as'nitrogen to increase the reaction temperature to the point where the catalyst is most active. Pressures of 50-760 mm. of mercury are suitable for this purpose. When gaseous olefinic compounds are employed, e. g., ethylene, the reaction can be carried out in metal reactors capable of withstanding the desired operating pressures, which can vary from 100 1b./sq. in. up to 1000 atm. or more. The lower pressures in this range, e. g., 100-1000 lb./sq. in., are used when it is desired to prepare a product having a molar ratio of one ethylene to one halosilane.

When products containing several moles of ethylene to one mole of halosilane are desired, higher pressures, e.-g., 1000 atm., are employed.

Conventional means for agitating chemical re- Ewample I s A solution of parts of trichlorosilane, 0.5 part of alpha,alpha' azobis(alpha,gamma dimethylvaleronitrile), and 2.0 parts of alpha,alpha azodiisobutyronitrile is placed in a stainless steel pressure reactor and ethylene added until the pressure reaches 400 lb./sq. in. The reaction mixture is heated, with agitation, to a temperature of 65-90 C. for a period of six hours with ethylene being added at intervals during this time tomaintain an internal pressure of 360-400 lb./sq. in. At the end of this reaction period the reactor is cooled and the excess ethylene bled off. The reaction mixture is then distilled, and after excess trichlorosilane is recovered, 21.8 parts of ethyltrichlorosilane boiling at 97-99 C. is obtained. This corresponds to a yield of 36%.

Example II A reaction is carried out in a manner similar to that of Example I except that the catalyst is a mixture of one part of alpha,alpha-'azodiisobutyronitrile and one part of 1,1'-azodicyclohexanecarbonitrile, and the reaction is carried out under ethylene pressure of 350-440 lb./sq. in. at a temperature ranging from 75 to 120 C. for a period of 13 hours. Under these conditions, 29.7 parts of ethyltrichlorosilane, corresponding to a yield of 50% of the theoretical, is obtained. There is also obtained 3.5 parts which time the reaction temperature increases gradually from 42 to C. The reaction mixture is then distilled, and, after recovering unchanged reactants, there is obtained 10 parts of octyltrichlorosilane, B. P.,144149 C./66 -mm. This represents. a 75% yield based on unrecovered l-octene.

Example IV A solution of 76 parts of trichlorosilane, 70 parts of 1-octadecene, 2 parts of alpha,a1pha"- azodiisobutyronitrile, and 1 part of l,1'-azodi- Example V A stainless steel pressure reactor is charged with 17.5 parts of butadiene, 41.5 parts of trichlorosilane, 1 part of alpha,alpha'-azodiisobutyronitrile, and 0.5 part of l,1'-azodicyclohex anecarbonitrile and heated to C. during about 1% hours. The temperature is then gradually raised to 115 C. during 14 hours, after which the reaction vessel is cooled and the reaction mixture distilled. After recovering unchanged butadiene and 'trichlorosilane, there is obtained a residue, amounting to 10 parts, of a moderately viscous yellow oil. This product is sensitive toward hydrolysis and analysis indicates that it is an addition product of 7 to 8 moles of butadiene per mole oftrichlorosilane.

Analysis:

Calculated tor (CLHB)'I-S -HCIE: Si, 5.4% CL 20.7% '(QHUaSiHClg: Si, 49%; CI, 18.8% Found: Si, 4.8% Cl, 19.6%

Example VI ture is distilled to remove unreacted trichloro silane, afterjwhich there is obtained 27.3 parts of a high boiling, yellow, slightly viscous liquid residue. Analysis of this residue indicates that it: is an addition product; containin fo molester: styrenezper mole; ortrich-lorosilane- Analysis:

Calc la o aHai Ch: 01. 44.4%

(osHBnsiHcn: s1, 5.1%.; 01, 19.3% Found: Si, 4.9%; (120.5%

When a small portion of the liquid residue is added to water it partially solidifies to a pasty mass which is nearly completely soluble in ether. The resulting ether solution is flowed onto a glass plate, and evaporation of the solvent leaves a colorless brittle film.

A mixture of 40 parts of 4-methyl-2-pentene, '70 parts of trichlorosilane and 2.0 parts of 1,1-. azodicyclohexanecarbonitrileplaced in a stainless steel reaction vessel capable- 01' with--. standing high pressure. The reactor is flushed out with dry nitrogen, closed, and. heated, with agitation, at 90 to 115 C. 01 1].- hours. After cooling, the reaction vessel is opened, and the contents fractionally distilled. There'is obtained '76parts, corresponding to 71-% of the theoretical, of aproduct boiling at 1'77-l.84 C. at atmospheric pressure, a mixture of the twoisomeric 1:1 addition products possible, 1-ethyl-2-methylpropyltrichlorosilane and. 1,3Pdimethylbutyltrichlorosilan-e. Analysis (calculated for CsHuSiCls)! C, 328%; 5.9%; Si, 12.8%. Found: C, 33.1%; H, 6.2%; Si, 1 2.5

Ex m le VIII A solution of 80 parts of; benzene. 5.0 Parts of. trichlorosilane, and one part of 1,1-azodicyclohexanecarbonitrile is placed, in a silver-lined steel-reacto and ethylene-injected to ap e u M2599: am, T tem ratur oi th x ur is aisedo C- nd ad i ional. th e e s e d il e sure ea he 1 .0 tm- Et ylenev s absorbe uite r pidly at i t d h pr ssure s ma ntaine 0. a n-b n er ttent addition of more ethylene. After 12 hours u qcrt cse.c ndi ns the r act s ccoled, a s thylene t d. an he eact o mixture distilled. Notrichlorosilane, and only atrace of the 1:1 addition product, are. obtained. There areisolated 13 parts of the addition product of two moles of ethylene, to one mole of trichlorosilane, boiling at 46-52 C ./1'7 mm.; 9 parts of the, 3:1 addition product, boiling at 80-35 (3/17 1pm.; 4 parts of the 4:1 addition, product, boiling at 90'-97 C./ mm.; 20 part-sv of a liquid addition. product of more than four moles of ethyleneto one mole of trichlorosilane, boiling at 97=200 C./5 mm.; and 15 parts of a solid residue, having, a still higher ratio of ethylene to tri-. chloro silane.

Ex p X...

A mixture of parts of 2,4,4-trimethyl-1- pentene, 81 parts of trichlorosilane, 2 parts of alpha,alpha azobis- (alpha,- gamma-dimethylvaleronitrile) and one part of alpha, alpha' -azodiisobutyronitrile is heated for 1-2'h ours at 60-65"- C; by the procedure of Example III. The reaction mixture is then distilled andthere is obtained 13 parts, corresponding to of the theoretical, of 2,4,4 trimethylpentyltrichlorov silane, boiling at 40 C. at 2 mm.

Analysis: Calculated-for CaHflSiGlz: Si, 11.35%; C1, 42.8%. Found: Si, 10.7%, 10.96%; C1. 39.47%, 39 .41%.

In addition to the specific reactions illustrated by the above examples, the process of-this invention; is applicable to the addition of'other halosilanes, having one silicon atom to which are joined-.-a hydrogenatom and a halogen, atom tine; eludingw fluorine, chlorine, bromine, and iodi e}, any other snbstituents on this silicon atombeing monovalent hydrocarbon radicalsfree frornnonaromatic unsaturation, to other organic; compounds containing at least one olefinicdouble bond; of aliphatic character. The operable halo-.- silanesinclude the monoand diaikyland monoand diarylhalosilanes haying one to three halo: genatoms. and one to. three hydrogen, atomsat; tachedto silicon. Specific halosilanes which can, be. used include HzSiClz, HSiBr3, HSiFa, Has-i 12, HaSiCl, C2H5HS1C12, (CH3)2HSiC1, CaHsHSiClz 'GGsH5).-zHSiCl and the like:

The.- unsaturated compounds operable; in. the; process-1 of this invention. are those. havingnatr. least one non-aromatic or olefinic double bond, i-.. e,-.. a. double bond aliphatic in character; 1n eluding. aliphatic and cycloaliphatic, between-two, carbons, and hydrogen on at least one. Qfgthflg doubly bonded-carbons. Monolefinic acyclic alir. phatic hydrocarbons. having from 2 to 18.,carbon: atoms. are'especially suitable; but high polymeric; olefinic hydrocarbons. such as rubber, and poly-= butadiene can be used. Specific examples off other olefinic compounds, which. can, be used in clude hydrocarbons such as propylene, 1-butenta iso-butylene, isoprene, 2-butene, cyclohexane, cy-

clohexadiene; olefinic esters such as allyl acetate,

' 1 vinyl acetate, methylmethacrylate, Z-furyl acrylate and linseed oil; heterocyclic compounds such as vinylpyridine; olefinic halides such as vinyl chloride andallyl chloride; and olefinic alcohols u h. as. a lyl alc ho relative proportions of theolefinic cornppund and the halosilane used in the practice of this invention can be varied widely, the preferred proportions depending in part on the type of olefinic compound being employed; In the case of nonpolymerizable olefinic compounds, e. g., octadecene, stoichiometric proportions can be used if desired, but since an excess of trichlorosilane tends to minimize side reactions, and since an, excess of the halosilane is readily recovered, it; is preferred to use an excess of the halosilane. In such cases a moderate excess such a 50% excess is suitable. With the polymerizable olefinic compounds, however, a larger excess ofthe halosilane is preferred in order to minimize telomer formation. For example, with compoundssuch as styrene, a 200% excess is preferred when low molecular weight telomers are desired. Smaller proportions of the halosilane, even amounts less than those stoichiometrically equivalent to the olefinic compound will add to the double bond of the olefinic compound, but the .yield of 1:1 addition product will be lower.

The examples have illustrated the use of certain azo compounds and mixtures of these as catalysts, or initiators, in the process of this invention. Although single azo compounds of the type defined above are effective in this process, it is often advantageous to use mixtures of two azo compounds which decompose at different temperatures since this provides a more gradual and smoother reaction. Thus, the particular azo compound which decomposes at the lower temperature catalyzes the addition of the halosilane to the olefinic compound during the first part of the reaction at the lower temperature, and the more stable azo compound then catalyzes the addition during the later stages of the reaction at the higher temperatures. This is a convenient way of providing catalytic activity over a longer-operiod of-time to increase the yield of desired products. In addition to the specific azo compounds illustrated in the example, which are symmetrical a'zo compounds wherein the valences of the acyclic azo, N=N, group are each attached to a monovalent radical, aliphatic in character, which is saturated hydrocarbon except for a cyano group on the alpha carbon which is tertiary, the following compounds, alone or in combination with these or other azo compounds, are operable: Dimethyl, diethyl, and dihexyl alpha,alpha-azodiisobutyrate, alpha,a1pha-azodiisobutyramide, which azo compounds can be prepared by the process of Thiele and Heuser Ann. 290, 1-43 (1896) alpha,alpha -azobis (alpha-methyl-gamma-carboxybutyronitrile), alpha,alpha-azobis- (alpha-methyl-beta-methoxypropionitrile), alpha,alpha'--azobis(alpha,gamma-dimethy1 gamma-ethoxyvaleronitrile) alpha,alpha-azbis (alpha-methyl-gamma diethylaminobutyronitrile) alpha,alpha' azobis(alpha methylcaprylonitrile) alpha,alpha' -azobis alpha -cyclopropylpropionitrile) alpha,alpha-azobis(alpha, beta, betatrimethylbutyronitrile) alpha,alpha' -azobis (alpha-cyclohexylpropionitrile), alpha,alpha'-azobis(alpha-phenylpropionitrile), the polymeric azon'itrile from 2,15-cetanedione having the formula ON ON which azo compounds can be prepared by the process of Alderson and Robertson, Serial No. 786,586; 1,1 azodicyclopentanecarbonitrile, which can be prepared by the process of Hartmann, Rec. trav. chim. 46, 150-153 (1927) Chem. weekblad 23, 77-78, January 1926; carbamy1azoisobutyramide, carbamylazo alpha,gamma-dimethylvaleramide, carbamylazohexyl-alpha,gamma-dimethylvalerate, and alpha-(carbamylazo)- isobutyronitrile which azo compounds can be prepared by the process of Robertson Serial No. 757,683an improvement over the process of 'Ihiele and Stange, Ann. 283, 33-37 (1894). The proportions of these operable azo compounds range'irom 0.91% to of the weight of the reactants. However, they are usually employed in amounts ranging from about 0.5% to about 3% ofthe weight of the reactants.

These azo compounds may be prepared b the general procedures described by Thiele and Stange, Ann. 283, 33-37 (1894) Robertson Serial No. 757,683,filed June 27, 1947; Thiele and Heuser, Ann. 290, 1-43 (1896) Hartmann, Rec. trav. chim. 46150-1573 (1927); Chem. weekblad 23, 77-78, January 1926; Box, J. A. C. S. 47, 1471-1477 (1925); and Alderson and Robertson Serial No. 736, 586, filed March 22, 1947. In the process of Alderson and Robertson Serial No. 736,586 the azine of an oxy carbonyl compound (aldehyde or ketone) of not more than 12 carbons is treated with an excess of hydrogen cyanide in a system containing not 'more than 50% water at room temperature or above. The resulting hydrazonitrile is then oxidized to the azonitrile by anoxidizing agent such as chlorine or bromine in the presence of an acid such as hydrochloric acid. In the process of Robertson Serial No. 757,683 hydrogen cyanide is added to the s micarbazone of a ketone followed by oxidation of the resulting semicarbazidonitrile with potassium permanganate. vThe Alderson and Robertson application Serial No. 736,586 is now U. S. Patent 2,469,358.

. {Ifhe superiority of the azo catalysts overperoxide type catalysts in initiating the reaction be ene under 530-600 lbs. per sq. in. pressure are heated at 7 0 to 90 C. in a stainless steel reactor for 15 hours in the presence of 1.5 parts of acetyl peroxide. V V

In view of the wide variety of organic compounds containing at least one olefinic double bond that can be used in the process of this invention, the products obtained are useful in a wide varietyrof applications. For example, they are useful as intermediates. They can be converted to the corresponding siliconic acids by hydrolyzing them to remove the halogen atoms. The siliconic acids polymerize readily, and in their polymerized form they are useful as modifiers for .various polymeric materials, for example as hardeners for alkyd resins.

The foregoing detailed description has been given for clearness of understanding only and no unnecessary limitations are to be understood therefrom. The invention is not limited to the exact details shown and described for obvious modifications will occur to those skilled in'the art.

What is claimed is: I

1. Process for the preparation of organosilicon compounds which comprises heating trichlorosilane with an acyclic aliphatic hydrocarbon containing but one unsaturation and that olefinic and having hydrogen on doubly bonded carbons in the presence of a symmetrical azo compound wherein the valences of the acyclic azo, -N=N, group are each attached to a monovalent radical, aliphatic in character, which is saturated hydrocarbon, except for a cyano group on the alpha carbon which carbon is tertiary.

2. Process for the preparation of organosilicon compounds which comprises heating trichlorosilane with a hydrocarbon, aliphatic in character, having an olefinic unsaturation and having hydrogen on doubly bonded carbon in the presence of a symmetrical azo compound wherein the valences of the acyclic azo, N=N, group are each attached to a monovalent radical, aliphatic in character, which is saturated hydrocarbon apart from a cyano group on the alpha carbon which carbon is tertiary.

3. Process for the preparation'of organosilicon compounds which comprises heating trichlorosilane with a hydrocarbon having an olefinic unsaturation and having hydrogen on olefinic doubly bonded carbon in the presence of a symmetrical. azo compound wherein the valences of the acyclic azo, N=N-, group are each attached to a monovalent radical, aliphatic in character, which is saturated hydrocarbon apart from a cyano group on the alpha carbon which carbon is tertiary.

4. Process for the preparation of organosilicon compounds which comprises heating trichlorosilan with an organic compound having at least one double bond, aliphatic in character, and having hydrogen on olefinic doubly bonded carbon in the presence of a symmetrical azo compound h ein th va enc s hea v N.=N-.

:group are eacn attache 'alir'fliatic in character, which is saturated hydrocarbon apart from a "cyano group on the alpha to a. m'cnovalent" radical,

carbon which carbcn is tertiary.

5. Process for the preparationof organosilicon compounds which comprises heating trichlorosilane with anorganic compound having an olefinic unsaturation and having hydrogen on ,ole-

{ finic doubly bonded carbon in the presence of an 'to acidity, by carbon of said radical which carbon has -it's three remaining valences satisfied by elements of atomic number -seven to eight.

6. Process of claim 5 'whereinthe azo catalyst is symmetrical.

'7. Process for the preparation of 'organosilicon compounds which comprises heating trichlorosilane with an organic compound having van olefim'c unsaturation and having hydrogen on olefinic doubly bonded carbon in the presence of an azo compound wherein both valences of 'tlie acyclic azo, N=N, group are attached to different non-aromatic carbons, at least one of which is tertiary and is attached to carbon of a negative radical which carbon has its three remaining valences satisfied by elements of atomic number of seven to eight.

8. Process of claim 7 wherein the azo compound has both valences of the acyclic azo, -N=N, group attached to different tertiary carbons aliphatic in character.

9. Process for the preparation of organosilicon compounds wherein a halosilane having hydrogen and halogen on the one silicon is heated with a compound having an olefinic linkage and having hydrogen on olefinic doubly bonded carbon in the presence of an azo compound wherein both valences of the acyclic azo, N=N, group are attached to different non-aromatic carbom, at least one of which is tertiary and is attached to carbon of a negative radical which carbon has its three remaining valences satisfied by elements of atomic number of seven to eight.

10. Process for the preparation of organosilicon compounds wherein a halosilane having hydrogen and halogen on the one silicon, any remaining valence of the silicon being bonded to monovalent radicals free from non-aromatic unsaturation is heated with a, compoundv having an olefinic linkage and having hydrogen on olefinic doubly bonded carbon in the presence of an azo compound wherein both valences of the acyclic azo, -N=N, group are attached to different non-aromatic carbons, at least one of which is tertiary and is attached to carbon of a negative radical which carbon has its three remaining valences satisfied by elements of atomic number of seven to eight.

11. Process for the preparation of organosilicon compounds which comprises heating trichlorosilane with an organic compound having an olefinic unsaturation and having hydrogen on olefinic doubly bonded carbon in the presence of an azo compound wherein both valences of the acyclic azo, N=N-, group are attached to different tertiary carbons aliphatic in character and at least one of which is attached to a radical of the class consisting of the cyano, CN, carbonamido, CONHz, and carbalkoxy, COO- Alkyl, groups.

12. Proce s for the pr paration of organonitrog'en'which carbon is tertiary.

si'llcon compounds which -comprises heating trichlorosilane with a hydrocarbon having an ole- -finic unsaturation and having hydrogen on olefinic doubly bonded carbon in the presence of a symmetrical azo compound wherein the valences of the acyclic azo, N=N, group are each atta'ched' to different tertiary carbons aliphatic in characterand each of said tertiary carbons is attachedto aradic'al' of the class consisting of the "cyano, CN, carbonamido, CONHz, and carbalkoxy, COO-Alkyl, groups.

13. Process for the preparation of organosilicon compounds which comprises heating a halosilane having hydrogen and halogen on the one silicon with a hydrocarbon having an olefinic unsaturation and having hydrogen on olefinic doubly bonded carbon in the presence of a symmetrical azo compound wherein the valences of the acyclic azo, N=N-, group are each attached toamonovalent radical, aliphatic in character, whichis saturated hydrocarbon apart from a' cyano group on the carbon attached to the azo tached to different tertiary carbons aliphatic in character and each of said tertiary carbons is attached to a radical of the class consisting of the cyano, CN, carbonamido, CONHz, carbalkoxy, COO-Alkyl, groups.

15. Process for the preparation of organo- I silicon compounds which comprises heating an inorganic halosilane having hydrogen and halogen on the one silicon with a hydrocarbon having an olefinic unsaturation and having hydrogen on olefinic doubly bonded carbon in the presence of a symmetrical azo compound wherein the valences of the acyclic azo, N=N, group are each attached to a monovalent radical, aliphatic in character, which is saturated hydrocarbon apart from a cyano group on the alpha carbon which carbon is tertiary.

16. Process for the preparation of organo-v silcon compounds which comprises heating an inorganic halosilane having hydrogen and halogen on the one silicon with an organic compound having at least one double bond, aliphatic in character, and having hydrogen on olefinic doubly bonded carbon in the presence of a symmetrical azo compound wherein the valences of the acyclic azo. N=N, group are each attached to a monovalent radical, aliphatic in character, which is saturated hydrocarbon apart from a cyano group on the alpha carbon which carbon is tertiary.

17. Process for the preparation of organosilicon compounds which comprises heating a halosilane having hydrogen and halogen on the one silicon atom, any remaining valences of which are satisfied by monovalent hydrocarbon radicals free from non-aromatic unsaturatiomwith a hydrocarbon having an olefinic unsaturation and having hydrogen on olefinic doubly bonded carbon in the presence of a symmetrical azo compound wherein the valences of the acyclic azo, N=N-, group are each attached to a monovalent radical, aliphatic in character, which is saturated hydrocarbon apart from a cyano group on the alpha carbon which carbon is tertiary.

free from non-aromatic unsaturation, with an organic compound having at least one double bond, aliphatic in character, and having hydrogen on oleflnic doubly bonded carbon in the presence of a symmetrical azo compound wherein the valences of the acyclic azo, N=N-, group are each attached to a monovalent radical, aliphatic in character, which is saturated hydrocarbon apart from a cyano group on the alpha carbon which carbon is tertiary.

19. Process for the preparation .of organesilicon cbmpounds which comprises heating trichlorosilane with a hydrocarbon having an olefinic unsaturation and having hydrogen von olefinic doubly bonded carbon in the presence of a symmetrical azo compound wherein the valences of the acyclic azo, N=N, group are each attached to a monovalent radical, aliphatic in character, which is saturated hydrocarbon apart from a monovalent group on the alpha, tertiary car- 12 bon which monovalent group is negative and has its free valence stemming from a carbon which has its three remaining valences satisfied byelements of atomic number of seven to eight.

9 ROBERT DE WALD LIPSCOMB.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS OTHER REFERENCES Sommer, J. A. c. s., vol. 69 (1947), age 188.

Burkhard, J. A. C. 8., vol. 69 (1947), pages 2687- 2689. a i V 7 Barry, J. A. C. 5., vol. 69 (1947) page 2916.

*Pietruza, J. A. C. 8., vol. '70 (1948), pages484- 

1. PROCESS FOR THE PREPARATION OF ORGANOSILICON COMPOUNDS WHICH COMPRISES HEATING TRICHLOROSILANE WITH AN ACYLIC ALIPHATIC HYDROCARBON CONTAIING BUT ONE UNSATURATION AND THAT OLEFINIC AND HAVING HYDROGEN ON DOUBLY BONDED CARBONS IN THE PRESENCE OF A SYMMETRICAL AZO COMPOUND WHEREIN THE VALENCES OF THE ACYCLIC AZO, -N=N-, GROUP ARE EACH ATTACHED TO A MONOVALENT RADICAL, ALIPHATIC IN CHARACTER, WHICH IS SATURATED HYDROCARBON, EXCEPT FOR A CYANO GROUP ON THE ALPHA CARBON WHICH CARBON IS TERTIARY. 